A comparison study of crevice corrosion on typical stainless steels under biofouling and artificial configurations

Abstract

In this work, the crevice corrosion behavior and biofouling coverage of 316L stainless steel (316L SS), 2205 duplex stainless steel (2205 DSS), and 2507 super duplex stainless steel (2507 SDSS) in natural seawater were investigated through long-term field exposure tests. The results revealed that both artificial crevice corrosion and biofouling-induced crevice corrosion occurred on the surface of three stainless steels. The corrosion rate was ranked as 316L SS » 2205 DSS＞2507 SDSS. The deepest area of the artificial corrosion pit was at the edge of the crevice, which was related to the IR drop and acidification of the localized solution. The highest biofouling coverage and the most severe biofouling-induced corrosion occurred on the surface of 316L SS. The attachment of large organisms to the metal surface formed a fouling barrier layer, further blocking the flow of material over the crevices, and the artificial crevice corrosion was accelerated. The initiation of barnacle-induced corrosion was due to the formation of a crevice between the barnacle and the substrate, resulting in the entry of seawater. The acidification of the solution caused by catalytic-occluded cells was responsible for the continuous development of barnacle-induced corrosion, which was similar to the propagation of the artificial crevice corrosion.